it was still difficult to get it apart but managed eventually. Is it possible to cut the fuel line and put in a fuel line joiner and a couple of clamps to make it easier to get apart in future with just a screwdriver?

There's tricks & technique. Once you've unplugged the fuel pump's electrical connector, punch the starter button to relieve any pressure in the line. Then push with one hand & pull with the other - that tool may help. Once apart, lube the inside of the connector lightly, it will help next time. While it's off, examine the allowed movement - you'll find it actually doesn't have much. Then you start practising. Until it becomes easy - that's technique. The more you do it, the easier it gets. A better connector may be easier, but now I know how, it's no longer necessary & I can cope comfortably. It's Italian - it works OK if you hold your tongue in the correct angle.

where he cut the line eventually and added a hose clamp. But I'm a bit reluctant to try to get the old clamp off the quick connector, and shorten the fuel line which is why I thought of adding a joiner in further down the line.

Couldn't get it apart without the pliers, even they bent and I had to straighten them and try from other side of bike. But they are very cheap things.

What would be best to lube inside of connector with? ACF50? Silcone spray/grease? WD40?

In the early days, and when I attend the tanks of others, if the connector seemed reluctant or stiff, I would try a little lube into the connector with the can's little tube. It would be really nice if that connector had a definite action, so you'd know, by feel or sound, whether you got it, or not. Unfortunately it doesn't.

That's the difference between wishing and knowing. The school of hard knocks is a good teacher - if you are awake!

Mal, on a side note, I am changing the design of those vacuum takeoffs to make them stronger. Got stupidly busy yesterday (with work would you believe - the shame). Hopefully I will get some made up this next week.

I ended up putting an inline connector in which is so much easier; I looked into it and it looks as though the nylon and plastic quick release adaptors should not be used on Fuel injection systems [don't know how true this is], any road the metal is more expensive.

[You must be registered and logged in to see this link.] something like this is what I got (both male and female)